/*

This file is part of Ext JS 4

Copyright (c) 2011 Sencha Inc

Contact:  http://www.sencha.com/contact

Commercial Usage
Licensees holding valid commercial licenses may use this file in accordance with the Commercial Software License Agreement provided with the Software or, alternatively, in accordance with the terms contained in a written agreement between you and Sencha.

If you are unsure which license is appropriate for your use, please contact the sales department at http://www.sencha.com/contact.

*/
/**
 * @class Ext.view.BoundListKeyNav
 * @extends Ext.util.KeyNav
 * A specialized {@link Ext.util.KeyNav} implementation for navigating a {@link Ext.view.BoundList} using
 * the keyboard. The up, down, pageup, pagedown, home, and end keys move the active highlight
 * through the list. The enter key invokes the selection model's select action using the highlighted item.
 */
Ext.define('Ext.view.BoundListKeyNav', {
    extend: 'Ext.util.KeyNav',
    requires: 'Ext.view.BoundList',

    /**
     * @cfg {Ext.view.BoundList} boundList
     * @required
     * The {@link Ext.view.BoundList} instance for which key navigation will be managed. This is required.
     */

    constructor: function(el, config) {
        var me = this;
        me.boundList = config.boundList;
        me.callParent([el, Ext.apply({}, config, me.defaultHandlers)]);
    },

    defaultHandlers: {
        up: function() {
            var me = this,
                boundList = me.boundList,
                allItems = boundList.all,
                oldItem = boundList.highlightedItem,
                oldItemIdx = oldItem ? boundList.indexOf(oldItem) : -1,
                newItemIdx = oldItemIdx > 0 ? oldItemIdx - 1 : allItems.getCount() - 1; //wraps around
            me.highlightAt(newItemIdx);
        },

        down: function() {
            var me = this,
                boundList = me.boundList,
                allItems = boundList.all,
                oldItem = boundList.highlightedItem,
                oldItemIdx = oldItem ? boundList.indexOf(oldItem) : -1,
                newItemIdx = oldItemIdx < allItems.getCount() - 1 ? oldItemIdx + 1 : 0; //wraps around
            me.highlightAt(newItemIdx);
        },

        pageup: function() {
            //TODO
        },

        pagedown: function() {
            //TODO
        },

        home: function() {
            this.highlightAt(0);
        },

        end: function() {
            var me = this;
            me.highlightAt(me.boundList.all.getCount() - 1);
        },

        enter: function(e) {
            this.selectHighlighted(e);
        }
    },

    /**
     * Highlights the item at the given index.
     * @param {Number} index
     */
    highlightAt: function(index) {
        var boundList = this.boundList,
            item = boundList.all.item(index);
        if (item) {
            item = item.dom;
            boundList.highlightItem(item);
            boundList.getTargetEl().scrollChildIntoView(item, false);
        }
    },

    /**
     * Triggers selection of the currently highlighted item according to the behavior of
     * the configured SelectionModel.
     */
    selectHighlighted: function(e) {
        var me = this,
            boundList = me.boundList,
            highlighted = boundList.highlightedItem,
            selModel = boundList.getSelectionModel();
        if (highlighted) {
            selModel.selectWithEvent(boundList.getRecord(highlighted), e);
        }
    }

});
